import { generateImageFrame } from "./openrouter.js";
import { buildGifFromFrames } from "./gif.js";
import { firstPrompt, nextFramePrompt } from "./ui.js";

const GEMINI_MODEL = "google/gemini-3.1-flash-image-preview";

const state = {
  apiKey: localStorage.getItem("openrouter_api_key") || "",
  frames: [],
  gifUrl: "",
  loading: false
};

const el = {};
const q = (id) => document.getElementById(id);

function clamp(n, min, max, fallback) {
  n = Number(n);
  if (Number.isNaN(n)) return fallback;
  return Math.min(max, Math.max(min, n));
}

function show(node) {
  node.classList.remove("hidden");
  if (node.id === "settings-modal") node.classList.add("flex");
}

function hide(node) {
  node.classList.add("hidden");
  if (node.id === "settings-modal") node.classList.remove("flex");
}

function setError(msg = "") {
  if (!msg) {
    el.error.textContent = "";
    hide(el.error);
    return;
  }
  el.error.textContent = msg;
  show(el.error);
}

function setProgress(label = "", pct = 0, visible = false) {
  el.progressLabel.textContent = label;
  el.progressBar.style.width = `${Math.max(0, Math.min(100, pct))}%`;
  visible ? show(el.progressWrap) : hide(el.progressWrap);
}

function setLoading(v) {
  state.loading = !!v;
  el.generateBtn.disabled = state.loading;
  el.generateBtn.textContent = state.loading ? "Generating…" : "Generate GIF";
}

function updateImageSizeOptions() {
  const model = el.model.value;
  const current = el.imageSize.value;
  const options = model === GEMINI_MODEL
    ? [
        { value: "1K", label: "1K" },
        { value: "0.5K", label: "0.5K" }
      ]
    : [{ value: "1K", label: "1K" }];

  el.imageSize.innerHTML = "";
  for (const opt of options) {
    const o = document.createElement("option");
    o.value = opt.value;
    o.textContent = opt.label;
    el.imageSize.appendChild(o);
  }

  const allowed = options.map((o) => o.value);
  el.imageSize.value = allowed.includes(current) ? current : "1K";
}

function renderFrames() {
  el.framesGrid.innerHTML = "";
  for (let i = 0; i < state.frames.length; i++) {
    const card = document.createElement("div");
    card.className = "rounded-xl border border-ui-border p-2 bg-white";

    const img = document.createElement("img");
    img.src = state.frames[i];
    img.alt = `frame ${i + 1}`;
    img.className = "w-full rounded-lg";

    const p = document.createElement("p");
    p.className = "mt-1 text-xs text-ui-sub";
    p.textContent = `Frame ${i + 1}`;

    card.appendChild(img);
    card.appendChild(p);
    el.framesGrid.appendChild(card);
  }
}

function renderGif() {
  if (!state.gifUrl) {
    hide(el.gifWrap);
    show(el.emptyOutput);
    return;
  }
  el.gifImg.src = state.gifUrl;
  el.gifDownload.href = state.gifUrl;
  show(el.gifWrap);
  hide(el.emptyOutput);
}

function openSettings() {
  el.apiKeyInput.value = state.apiKey;
  show(el.settingsModal);
}

function closeSettings() {
  hide(el.settingsModal);
}

function saveApiKey() {
  state.apiKey = el.apiKeyInput.value.trim();
  localStorage.setItem("openrouter_api_key", state.apiKey);
  closeSettings();
}

function clearApiKey() {
  state.apiKey = "";
  el.apiKeyInput.value = "";
  localStorage.removeItem("openrouter_api_key");
}

async function generate() {
  setError("");
  setLoading(true);
  setProgress("", 0, true);

  if (state.gifUrl) URL.revokeObjectURL(state.gifUrl);
  state.gifUrl = "";
  state.frames = [];
  renderGif();
  renderFrames();

  const model = el.model.value;
  const userPrompt = el.userPrompt.value.trim();
  const frameCount = clamp(el.frameCount.value, 2, 24, 4);
  const fps = clamp(el.fps.value, 1, 24, 6);
  const imageSize = el.imageSize.value;
  const aspectRatio = el.aspectRatio.value;

  if (!state.apiKey) {
    setError("Add your OpenRouter API key first (☰ button).");
    openSettings();
    setLoading(false);
    setProgress("", 0, false);
    return;
  }

  if (!userPrompt) {
    setError("Please enter a simple prompt (e.g. rolling cat).");
    setLoading(false);
    setProgress("", 0, false);
    return;
  }

  try {
    const p1 = firstPrompt(userPrompt);
    setProgress(`Generating frame 1/${frameCount}...`, Math.round(100 / frameCount), true);

    const frame1 = await generateImageFrame({
      apiKey: state.apiKey,
      model,
      textPrompt: p1,
      previousFrames: [],
      imageSize,
      aspectRatio
    });

    state.frames.push(frame1);
    renderFrames();

    for (let i = 2; i <= frameCount; i++) {
      setProgress(`Generating frame ${i}/${frameCount}...`, Math.round((i / frameCount) * 100), true);

      const next = await generateImageFrame({
        apiKey: state.apiKey,
        model,
        textPrompt: nextFramePrompt(frameCount),
        previousFrames: state.frames.slice(-2),
        imageSize,
        aspectRatio
      });

      state.frames.push(next);
      renderFrames();
    }

    setProgress("Building GIF...", 100, true);
    state.gifUrl = await buildGifFromFrames(state.frames, fps);
    renderGif();
    setProgress("Done.", 100, true);
  } catch (e) {
    setError(e?.message || "Failed to generate.");
    setProgress("", 0, false);
  } finally {
    setLoading(false);
  }
}

function bind() {
  el.openSettingsBtn.addEventListener("click", openSettings);
  el.closeSettingsBtn.addEventListener("click", closeSettings);
  el.saveApiKeyBtn.addEventListener("click", saveApiKey);
  el.clearApiKeyBtn.addEventListener("click", clearApiKey);
  el.generateBtn.addEventListener("click", generate);
  el.model.addEventListener("change", updateImageSizeOptions);

  el.settingsModal.addEventListener("click", (e) => {
    if (e.target === el.settingsModal) closeSettings();
  });

  document.addEventListener("keydown", (e) => {
    if (e.key === "Escape") closeSettings();
  });
}

function init() {
  el.model = q("model");
  el.userPrompt = q("user-prompt");
  el.frameCount = q("frame-count");
  el.fps = q("fps");
  el.imageSize = q("image-size");
  el.aspectRatio = q("aspect-ratio");
  el.generateBtn = q("generate-btn");
  el.error = q("error");
  el.progressWrap = q("progress-wrap");
  el.progressLabel = q("progress-label");
  el.progressBar = q("progress-bar");
  el.gifWrap = q("gif-wrap");
  el.gifImg = q("gif-img");
  el.gifDownload = q("gif-download");
  el.emptyOutput = q("empty-output");
  el.framesGrid = q("frames-grid");

  el.settingsModal = q("settings-modal");
  el.openSettingsBtn = q("open-settings-btn");
  el.closeSettingsBtn = q("close-settings-btn");
  el.apiKeyInput = q("api-key-input");
  el.saveApiKeyBtn = q("save-api-key-btn");
  el.clearApiKeyBtn = q("clear-api-key-btn");

  updateImageSizeOptions();
  renderGif();
  bind();
}

if (document.readyState === "loading") {
  document.addEventListener("DOMContentLoaded", init);
} else {
  init();
}